There are only 51 Ark Delegates that can actively forge. Some are private but most are public pools. I would recommend reading through Ark Delegate proposals to view and determine which each delegate offers in return for your vote. Here is a list of Delegate proposals on the ARK.io Forum. Also, you can use profit sharing calculators to help give a rough estimate on expected payout.

Here’s a blog post from the ARK.io Medium page on the process of voting with the ARK Wallet.